This should be supported, but we currently have a known issue with the AP7522E being converted via upgrade to v5.9.2:
AP7522E v5.9.2.1 ignores adopt request from regular sku AP75xx with the following message.
Jul 24 15:10:10 192.168.3.158 2018-07-24T15:12:17.010422-07:00 AP7522VC DPD2: 2018-07-24 15:12:17 mlcp.c:946 mlcp_handle_discover Ignoring discover from non-WiNG Express device
We have SPR (Software Problem Report) #3484 against this issue and issue will be resolved in a future v5.9.x release.
For the time being, I would not configure an AP7522E v5.9.2 as VC redundant until we resolve SPR #3484.